The Aphex 622 2-Channel Logic-Assisted Expander Gate is one of the best commercially available noise gates. Provides you with the lowest distortion, widest frequency response, and no clicks. Ultra-quiet and reliable. Can be used in recording and live performance. the Aphex 622 features Logic Assisted Gate Circuitry, an ultrapure audio path with voltage-controlled attenuator to assure highest quality audio, dedicated downward expander mode, parametric key input filters, switchable ducking mode, simple and accurate metering, and servo-balanced input and output circuits.